PC connection to router drops every hour

Short description: My PC's connection to our cable modem dies and reconnects once an hour. Other devices connected to the cable modem don't lose connection and remain connected to the internet while this happens. This happens regardless of which network card / wireless card I use on my PC, or which port on the modem I'm connected to.

Modem: Cisco EPC3925 modem
PC: Windows 7
Motherboard: Asus Z97 Deluxe (NFC & WLC)
Network Adaptor #1: Intel® I218-V Gigabit LAN
Network Adaptor #2: Intel® I211-AT Gigabit LAN
Wifi Adaptor: Broadcom 802.11ac (VEN_14E4&DEV_43B1)

Troubleshooting tried: Reboot PC, power cycle modem, reset modem (using pin), latest drivers asus support installed. Disabled network card option to allow PC to deactivate it.

Additional details: I only notice this problem when I'm playing World of Warcraft (WoW), as I'm relying on the connection to be able to play. I don't notice this problem any other time. However, as the connection comes back again almost instantly (within 10 seconds), I doubt I would notice it any other time.

I only noticed this morning that it's happening on the hour. This morning so far 08:44, 09:44, 10:44.

Any help greatly appreciated as this is a very frustrating problem for a WoW player.